You think so? How many months did the Wii win and much did third party support it?
The Wii did get pretty good 3rd party support for a time, all things considered. But the technical gap was much more difficult to bridge. Unreal Engine 4, Snowdrop, and now id Tech 6 all run on the Switch. These are all signs the Switch can handle a much larger percentage of current gen games than the Wii could handle of PS360 games. Honestly, id and Bethesda feeling Doom can come to Switch in good shape is a big deal with regards to this.
And the Switch has a standard control interface with 14 clickable inputs and two analogue sticks. The Wii had no analogue stick out of the box, only had 1 with the nunchuck, was lacking buttons. Developing a game for Wii necessitated adapting it to motion controls and fewer buttons or tying it to the classic controller pro peripheral which would limit sales potential.
In short, radically different situations.